This invention relates to the field of blowers. In particular, this invention is drawn to blower impeller design.
Cabinetry or enclosures for heat generating equipment may contain one or more blowers for active or forced air cooling. The blower displaces the air within the enclosure volume with cooler air external to the enclosure volume. The blower acts as a pump to exchange air inside the enclosure with air external to the enclosure. Typically, the blower is mounted such that the blades are,near the enclosure wall. A guard or cage is often used to prevent objects external to the enclosure from contacting the spinning blades. Once inside the enclosure, however, there is no protection from the spinning blades.
The equipment can be powered down to minimize any risk of contacting exposed blades within the enclosure. Computer servers are often specifically designed with hot pluggable modules. Hot pluggability enables replacing the modules without powering the equipment down in order to ensure a high level of availability. Powering down the equipment before servicing defeats the purpose of designing the equipment for hot pluggability.
In view of limitations of known systems and methods, a variety of blower fan brakes for equipment enclosures are disclosed. One apparatus includes a module configured for insertion into an enclosure. The module includes at least one blower having an impeller with a plurality of blades. A fan brake engages the impeller when the module is at least partially removed from the enclosure. The fan brake disengages the impeller when the module is inserted into the enclosure.
One blower apparatus includes an impeller having a plurality of blades, a braking surface, and an arm coupled to the braking surface. The arm applies the braking surface to the impeller when disengaged by a cam. The arm retracts the braking surface from the impeller when engaged by the cam.
In various embodiments, the braking surface is applied to the impeller body or the blades. The braking surface may be contoured in a shaped complementary to that of a portion of the periphery of the impeller body. Alternatively, the braking surface may comprise a flap for braking the blades. In some embodiments, a solenoid is used in lieu of the cam for either directly or indirectly applying the braking surface to the impeller upon removal of power.
Other features and advantages of the present invention will be apparent from the accompanying drawings and from the detailed description that follows below.